Are Keto Diets Good for Us?

Today, we take a look at the popular Keto diet, the high-fat, low-carb, moderate-protein diet that puts the body in a metabolic state called ketosis. And we start with the effect of the Keto diet on LDL cholesterol, with Dr. Dennis, our new Senior Research Scientist.

The effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on caloric intake and weight loss. A plant-based diet without sugary refined-grain foods versus a keto diet with a lot of vegetables. After two weeks randomized to one of the two diets, the participants were switched to the other one for another two weeks. Looking at the scale, guess who lost more body weight? Those on the low-carb diet.

But guess who lost more body fat? Those on the low-fat diet. In fact, there was no significant fat loss on the low-carb diet, whereas two pounds (1 kg) of fat were lost on the low-fat diet. What they were losing on the low-carb diet was fat-free mass, like water weight, but muscle, too. While fat-free mass was relatively preserved while on the low-fat diet, fat-free mass decreased on the low-carb diet, and there was evidence that the participants were losing muscle mass, despite eating more protein than when they were on the plant-based diet.

But when they were eating almost no carbs, their blood sugars were certainly lower. Does a ketogenic diet have a place within diabetes clinical practice? It’s even been suggested that low-carb diets could put type 2 diabetes into remission, which can be defined as an HbA1c, a marker of blood sugar control, lower than 6.5% for at least three months after stopping any blood sugar-lowering medications. But high blood sugars are just the symptom. The disease is one of carbohydrate intolerance. If you’re allergic to peanuts and don’t have symptoms because you avoid peanuts, you’re just managing the disease, not curing it. Curing a peanut allergy would mean being able to eat peanuts like anyone without a peanut allergy. It’s the same with carbohydrates and type 2 diabetes. True remission would be being able to eat carbohydrates like everyone else without getting adverse effects.

As Dr. Greger has covered, low-carb diets can actually make diabetes worse, worsening insulin resistance and increasing intolerance to carbohydrates. That would only be a problem, though, if you resumed eating carbohydrates. Why not just stick to a ketogenic diet forever?

What is the efficacy and safety of low-carb diets for type 2 diabetes remission? First of all, it didn’t work. Using the “under 6.5% and off all diabetes medications” definition of remission, there was no significant effect at 6 months, and at 12 months there was less remission, meaning more diabetes in the low-carb groups, along with clinically important harms on quality of life and the deal-killer—an increase in LDL cholesterol.

LDL cholesterol, commonly known as bad cholesterol, is unequivocally recognized as the principal driving force in the development of atherosclerotic cardiovascular disease, the leading cause of death for both men and women.

Basically, we should try to get our LDL as low as possible. Lower for longer is better. Even if our LDL is normal, even if other heart disease risk factors are considered optimal, it is of utmost importance to control our LDL. If LDL is the primary driver of our primary killer, then if we could just know one thing about a diet, if there were only one question we could ask about some new diet someone tells us about, it would be: “What does this diet do to my LDL cholesterol?”

If you follow people on lower carb diets over time and see what happens to their coronary artery calcium scores, which signify the progression of coronary artery disease, you’ll find that the low-carb group had the highest incidence of coronary artery calcium worsening––though this was only the case with animal based low-carb diets, not plant-based ones. But those who started eating low-carb diets rich in animal protein and fat in early adulthood had an increased risk of coronary artery calcium progression in middle age.

Of course, all carbs are not created equal. Carbs that are detrimental to our health, like sugars and refined grains, need to be distinguished from those with beneficial effects. When the American Heart Association looked at dietary patterns at a population level and ranked them from the most to the least aligned with its dietary guidance for heart health, how did low-carbohydrate diets rank? Poorly. In fact, they were ranked the worst. Even when very low-carb diets are followed optimally, they promote restriction of foods considered essential to heart health, like legumes and whole grains, and include high-saturated-fat sources like meat and dairy, which are both strongly discouraged.

In our next story, Keto diets are put to the test for diabetes reversal.

Ketogenic diets can certainly lower blood sugars, better than conventional diets—so much so, there is a keto product company that claims ketogenic diets can “reverse” diabetes. But they are confusing the symptom—high blood sugars—with the disease, which is carbohydrate intolerance. People with diabetes can’t properly handle carbohydrates, and this manifests as high blood sugars. Sure, if you stick to eating mostly fat, your blood sugars will stay low, but you may be actually making the underlying disease worse, at the same time.

We’ve known for nearly a century that if you put people on a ketogenic diet, their carbohydrate intolerance can skyrocket—within just two days.

One week on an 80% fat diet, and you can quintuple your blood sugar spike in reaction to the same carb load, compared to a week on a low-fat diet. Even a single day of excessive dietary fat intake can do it. If you’re going in for a diabetes test, having a fatty dinner the night before can adversely affect your results. One meal high in saturated fat can make the cause of diabetes—carbohydrate intolerance—worse within four hours.

Now, with enough weight loss by any means—whether from cholera or bariatric surgery—type 2 diabetes can be reversed. But a keto diet for diabetes may not just be papering over the cracks, but actively throwing fuel on the fire.

I’ve been trying to think of a good metaphor. It’s easy to come up with things that just treat the symptoms without helping the underlying disease, like giving someone with pneumonia aspirin for their fever, instead of antibiotics. But a keto diet for diabetes is worse than that, because it may treat the symptoms while actively worsening the disease. So, maybe it’s more like curing the fever by throwing that pneumonia patient out into a snow bank. Or maybe “curing” your amputated finger by amputating your hand. No more unsightly finger stub! One of the co-founders of masteringdiabetes.org suggested it’s like a CEO that makes their bad bottom line look better by just borrowing tons of new cash. The outer numbers look better, but on the inside, the company is just digging itself into a bigger hole.

Remember “The Club”? Maybe I just watched too much late-night TV growing up, but it’s a car anti-theft device that attaches to your steering wheel and locks it in place, so the steering column can only turn a few inches. Imagine you’re in a car at the top of a hill with the steering wheel locked. Then, the car starts rolling down the hill. What do you do? Oh, did I mention there’s also something stuck under your brake pedal too? The keto-diet-equivalent-response to this situation is who cares if you’re barreling down into traffic with no brakes and a locked steering wheel. Just stick to really straight deserted roads without any stop signs or traffic lights. If you do that, problem solved! Yeah, the longer you go, the more speed you’ll pick up, and so, if you should hit a dietary bump in the road, or start to veer off the path, the consequences could get more and more disastrous with time. But if you stick to the keto straight and narrow, you’ll be A-OK. In contrast, the non-keto response would be to just unlock the steering wheel and dislodge whatever’s under your brake. In other words, fix the underlying problem, instead of just whistling past (and then into) the graveyard.

The reason keto proponents claim they can “reverse” diabetes is that they can successfully wean type 2 diabetics off their insulin. But that’s like faith healing someone out of the need for a wheelchair by making them lie in bed the rest of their life. No need for a wheelchair if you never move. Their carbohydrate intolerance isn’t gone; their diabetes isn’t gone. It could be as bad or even worse. Type 2 diabetes is reversed when you can wean people off insulin eating a normal diet like everyone else—then and only then do you not have diabetes anymore. A true diabetes reversal diet is practically the opposite of a ketogenic diet; diabetics off their insulin within a matter of weeks, eating more than 300 grams of carbs a day.

The irony doesn’t stop there. One of the reasons diabetics suffer such nerve and artery damage is due to an inflammatory metabolic toxin known as methylglyoxal that forms at high blood sugar levels. Methylglyoxal is the most potent creator of advanced glycation end products, so-called AGEs, which are implicated in degenerative disease from Alzheimer’s disease and disease in cataracts to kidney disease and strokes. You get AGEs in your body from two sources: eating them preformed in your diet, or making them internally from methylglyoxal if you have high blood sugar levels. On a keto diet, one would expect high exposure to the preformed AGEs, since they’re found concentrated in animal-derived foods high in fat and protein. But we would expect less internal new formation due to presumably low levels of methylglyoxal, given lower blood sugars, not eating carbs. Dartmouth researchers were surprised to find more methylglyoxal, though. A few weeks on the Atkins diet led to a significant increase in methylglyoxal levels, and those in active ketosis did even worse—doubling the level of this glycotoxin in their bloodstream. It turns out high sugars may not be the only way to create this toxin.

One of the ketones you make on a ketogenic diet is acetone (known for its starring role in nail polish remover). Acetone does more than just make keto dieters fail breathalyzer tests and develop what’s been described as “rotten apple breath.” Acetone can oxidize in the blood to acetol, which may be a precursor for methylglyoxal. That may be why keto dieters can end up with levels of this glycotoxin as high as those with out-of-control diabetes, which can cause the nerve damage and blood vessel damage you see in diabetics. That’s another way keto dieters can end up with a heart attack. So, the irony of treating diabetes with a keto diet may extend beyond just making the underlying diabetes worse, but by mimicking some of the disease’s dire consequences.